Modular pneumatic surgical drill

ABSTRACT

A pneumatically driven turbine type drill has a modular casing that provides an air supply passage leading from a rear inlet and including an annular chamber leading to a front annular entry to the turbine and that provides an air exhaust passage leading from a sump at the rear of the turbine through a straight bore to a rear exit.

United States Patent [191 Cromie [11] 3,832,088 [451 Aug. 27, 1974 1MODULAR PNEUMATIC SURGICAL DRILL [75] Inventor: Harry W. Cromie,Pittsburgh, Pa.

[73] Assignee: Baxter Laboratories, Inc., Morton Grove, Ill.

[22] Filed: Sept. 20, 1971 [21] Appl. No.: 181,999

[52] US. Cl 415/199 R, 32/26, 415/503 [51] Int. Cl A6lc 1/05, F0ld 1/10,A6lb 17/32 [58] Field of Search 415/502, 503, 150, 199.;

[56] References Cited UNITED STATES PATENTS 4/1952 YOst 175/100 4/1964DeGroff ..32/26 Mothre 415/502 3,695,367 10/1972 Catterfeld et a1415/503 3,707,336 12/1972 Theis et al. 415/503 3,709,630 l/1973 Pohl eta1 415/503 Primary Examiner--Al1an D. Herrmann Attorney, Agent, orFirmJ. Patrick Cagney; W. Garrettson Ellis [57] ABSTRACT A pneumaticallydriven turbine type drill has a modular casing that provides an airsupply passage leading from a rear inlet and including an annularchamber leading to a front annular entry to the turbine and thatprovides an air exhaust passage leading from a sump at the rear of theturbine through a straight bore to a rear exit.

11 Claim, 3 Drawing Figures MODULAR PNEUMATIC SURGICAL DRILL BACKGROUNDOF THE INVENTION This invention relates to pneumatically actuatedsurgical drills having a turbine-type drive and, more particularly, isconcerned with a drill arrangement that is more compact, more efficientand easier to manufacture than the prior art drills.

Many of the prior art surgical drills of the turbinepowered type arearranged to vent the spent air at the front of the drill. This isobjectionable because front venting will dry out the living tissuesagainst which the surgical drill is working. The back venting types ofsur-' gical drills are known for avoiding this difficulty but suchdrills utilize forwardly moving air to power the turbine and require theexhaust air to traverse a 180 turn for back venting. Substantial backpressures occasioned by the 180 turn reduce thepower of the drill.

In addition, the prior art drill constructions utilize more complicatedhousing sleeves and transverse porting together with intricate internalflow channels that SUMMARY OF THE INVENTION The present inventionprovides a pneumatically actuated surgical drill that overcomes theabove-noted disadvantages of the prior art drills. In the embodimentdisclosed herein, a surgical drill of the turbine-operated type isprovided with a unique back-venting air passage network which leadsforwardly of the turbine to drive the turbine with rearwardly travellingair and exists through a low back pressure exhaust path. In addition,the invention provides a modular casing arrangement wherein complex airflow passages can readily be drilled thereby facilitating massproduction and reducing manufacturing costs. The air flow passagearrangement is controlled by an in-line valve contoured to facilitatevariable speed control in accordance with the position of a rearwardlyshiftable slidable trigger. The trigger can be shifted forwardly toapply braking action on the turbine spindle and/or to control releaseand gripping of a front mounted collet structure on a tool bit that isto be in the drill.

Other features and advantages of the invention will be apparent from thefollowing description and claims and are illustrated in the accompanyingdrawings which show structure embodying preferred features of thepresent invention and the principles thereof, and what is now consideredto be the best mode in which to apply these principles.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings forming apart of the specification, and in which like numerals are employed todesignate like parts throughout the same:

FIG. 1 is a lengthwise sectional view of the modular surgical drillconstructed in accordance with this invention;

FIG. 2 is an enlarged transverse sectional view taken on the line 2--2of FIG. 1; and

FIG. 3 is a fragmentary lengthwise section taken as indicated on theline 3--3 of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the drawings andparticularly to FIG. 1 thereof, a pneumatically driven surgical drill isillustrated as including a modular casing assembly designated generallyat MC and including a turbine housing 10, a trigger section 11, a valvesection 12, a valve cylinder section 13, and an end connection headsection 14. Each of the sections 11 through 13 is of right circularconfiguration and is machined with accurately fitting flat end faces andlengthwise extending bolt passages and air channels for assembly instacked axial alignment in successive end to end contacting relation tobe secured to the rear of the turbine section by elongated bolts B (seeFIGS. 2 and 3) that nest in countersunk relation in the valvecylindersection 13 and anchor in tapped holes H provided at the rear of theturbine housing l0. The connector head section 14 is threaded onto therear end of the valve cylinder section 13 to mask the bolts B and isprovided with an inlet fitting 15 for attachment to a source ofpressurized air (not shown). The end face of the head section 14 isprovided with rearwardly directed air exhaust port 14? for rearwarddischarge of the spent air. I

A turbine assembly located within the turbine section 10 includes arotor sleeve 16 having a drive spindle l7 slidably mounted therein insplined or keyed engagement to rotate in unison with the rotor sleevewhile accommodating axial shifting of the spindle 17. A three stageturbine arrangement is illustrated as including front, center and rearrotary turbine blade assemblies 18F, 18C and 18R separated by stationaryturbine blade assemblies 19 and secured on the rotor shaft by a lock nutN.

The rotor sleeve 16 has an enlarged diameter integral front extension16F that is threadedly connected to a stepped diameter chuck 20 todefine a chamber 20C for a coil bias spring 205 that encircles theforwardly extending portion of the drive spindle 17. The spindle l7terminates in an integral front collet structure 17C normally biasedinwardly into wedging engagement with the chuck 20 for tightly clampinga tool bit (not shown).

The turbine housing includes a rear attachment section 21 in which theassembly bolts B are anchored. The attachment section 21 has anexternally threaded portion screwed into the rear end of the mainturbine housing shell 22 which has an in-turned forward flange 22Fsecurely supporting a chuck housing 23.

The forward end of the attachment section 21 has a forwardly projectingannular ring 21R serving to accurately position a stationary supportsleeve 24 that carries the stationary turbine blade assemblies 19. Abearing assembly 25 is mounted between the chuck 20 and the chuckhousing 23. A bearing assembly 26 is mounted between the rotor sleeve 16and the rear of the chuck housing 23 and a bearing assembly 27 ismounted between the rear of the rotor sleeve 16 and the rearmoststationary turbine blade assembly 19.

An elongated annular air supply passage 28 is defined between stationarysleeve 24 and the main housing shell 22 to lead forwardly completelybeyond the front turbine blade assembly 18F and open into an annularfront region to direct the air rearwardly in substantially unifonnlydistributed relation (see arrow A in FIG. 1') into the front turbineblade assembly for rearward passage through the turbine. Thus, inoperation, the pressurized air impartsrotation to the rotary turbineblades 18F, 18C and 18R, the rotor sleeve 16, the drive spindle 17 andthe chuck 20, while the main shell 22 of the turbine housing, thestationary sleeve 24 and the chuck housing 23 remain stationary.

An air inlet passage 14A is shown leading axially through the rear headsection 14 and includes a region 13A leading into the valve chambersection 13 which includes an eccentrically located enlarged passage 13Cfor a return spring 29. The air inlet passage then leads through a valveseat chamber 12C which has a jogged passage region 12A (see FIG. 3)communicating with a through bore 11A provided in the trigger section11. The triger section 11 also has a valve guide passage [IV for anactuating rod 30 which is formed integrally with a valve 31 that has atapered flow control surface to accommodate variable air flow control.The through bore 11A of the trigger section communicates with an in-linebore portion 21A provided at the rear of the attachment section. Thein-line bore portion merges with an oblique bore portion 218 that opensinto the circular forwardly extending air supply passage 28 to leas theincoming air around the front of the turbine for rearward flow throughthe turbine.

The air exhaust passage includes an enlarged sump chamber E of generallyfrusto-conical form in the front end of the attachment section to facethe rear end of the turbine section. The sump 21E communicates insubstantially uniformly distributed relation with the rear region of theturbine means and communicates with an angled bore 21E leading throughthe attachment section 21. The remainder of the exhaust passage consistsof aligned bores 11E, 12E and 1312, respectively, provided in thetrigger section 11, valve seat section 12 and valve chamber section 13.Since the head section 14 is threadedly mounted, it is provided with anannular exhaust chamber region 14E so that there is communication withthe exhaust outlet of the valve chamber section 13 for any rotaryposition of the head section 14. The annular exhaust chamber 14E thenleads through the plurality of rearwardly directed vent passages 14F todirect the spent air away from the living tissue to which the drill isbeing applied.

A hand trigger 32 is shown slidably mounted upon the main shell 22 andit includes an integral connector stem 32S projecting transversely intoa generally rectangularly shaped socket 115 that is provided in thetrigger section. The connector stern 325 is secured by a lock pin 32F toan axial rod 33 which is slidably mounted in aligned guide boresprovided in the trigger section and the attachment section.

When the trigger 32 is shifted to its full forward position, the sliderod 33 abuts and shifts the drive spindle 17 to project the colletstructure 17C forwardly of the chuck and allow a tool bit to be insertedtherein. Forward movement of the collet 17C is resisted by the returnspring 205 contained in the chuck. Upon release of the trigger 32, thereturn spring 208 restores the spindle 17 to its operating position andcauses the collet 17C to be wedged tightly in the chuck 20 for holdingthe tool bit.

When the trigger 32 is shifted rearwardly, the valve 31 is progressivelyraised away from its valve seat ring 31R. The effective size of the portbetween the valve 31 and valve seat ring depends upon the extent ofrearward travel imparted to the trigger. Correspondingly, the flow rateof the incoming air is regulated inaccordance with the travel impartedto the valve by the trigger so that a variable speed effect is achieved.During use of the tool, the trigger 32 may be advanced partly fowardlywhereupon the valve return spring 29 restores the valve shutting off airsupply. In addition, the guide rod 33 establishes contact with the rearend of the spindle 17 to produce a friction braking action for limitingdrill rotation.

From the drawings and the foregoing disclosure, it will be noted thatthe air follows a reversal path as indicated by the arrows A at thefront of the turbine blade assemblies and undergoes expansion duringrearward flow through the successive sets of turbine blades to drive therotary mechanisms. The spent air exiting from the rear turbine bladeassembly 18R expands into an enlarged sump 10E that connects straight tothe rear of the casing MC through aligned exit bores 21E, 11E, 12E and1315 to allow exhaust of the air at minimum back pressure. Thisarrangement maximizes the power developed by the drill by minimizing thepresence of restrictions in the flow path of the high velocity, highvolume expanded air flow.

It should also be noted that the modular casing con struction allows thevarious bores and chambers to be drilled with accurate high volumeproduction techniques. Each of the casing sections 11 to 14 and 21 iscircular and has end faces for easy axial and rotary alignment. Thebores are machinable from the end face to allow for jogs and angles inthe passage profile. The common set of bolts B holds these sections inpredetermined registered alignment.

Thus, while preferred constructional features of the invention areembodied in the structure illustrated herein, it is to be understoodthat changes and variations may be made by those skilled in theartwithout departing from the spirit and scope of the appended claims.

What is claimed is:

1. in a pneumatically driven turbine type surgical drill that includescasing means having turbine means rotatably mounted therein, releasabletool holding means operable by said turbine means, and trigger means forcontrolling supply of compressed air to said turbine means, theimprovement wherein said casing means has an air flow passage networkincluding an air inlet located rearwardly of said turbine means, an airsupply passage leading from said inlet to a front region of saidturbine'means for rearward flow through said turbine means to impartrotation thereto and an air exhaust passage leading from a rear regionof the turbine means to an exit located rearwardly of said turbinemeans.

2. in a drill as defined in claim 1 and wherein said casing meansincludes concentric telescoping sleeves encircling said turbine meansand defining an elongated annular air supply passage region fordirecting incoming air to an annular front region of said turbine meansfor directing the air rearwardly in substantially uniformly distributedrelation into the turbine means.

3. in a drill as defined in claim 1 and wherein said exhaust passageincludes a sump region communicating in substantially uniformlydistributed relation with the rear region of the turbine means, and asubstantially straight bore communicating with the sump region andextending through the casing means to exhaust through said exit at theextreme rear region of said casing means.

4. In a drill as defined in claim 3 and wherein said casing meansincludes concentric telescoping sleeves encircling said turbine meansand defining an elongated annular air supply passage region fordirecting incoming air to an annular front region of said turbine meansfor directing the air rearwardly in substantially uniformly distributedrelation into the turbine means.

5. In a pneumatically driven turbine type surgical drill that includescasing means having turbine means rotatably mounted therein, releasabletool holding means operable by said turbine means, and trigger means forcontrolling supply of compressed air to said turbine means, theimprovement wherein said casing means comprises a modular casingassembly that includes a turbine housing having a rear attachmentsection, a trigger section, a valve section and a valve cylinder sectionin successive axial alignment, each of said sections having a separateendwise opening air supply passage portion and a separate endwiseopening air exhaust passage portion, and means securing said sections inend to end contacting relationship wherein the air supply passageportions are in successive registry to define an air supply passage andthe air passage portions are in successive registry to define an airexhaust passage. I

6. In a drill as defined in claim 5 and wherein said turbine housingincludes concentric telescoping sleeves encircling said turbine meansand defining an elongated annular air supply passage region fordirecting incoming air to an annular front region of said turbine meansfor directing the air rearwardly in substantially uniformly distributedrelation into the turbine means.

7. In a drill as defined in claim 6 and wherein said exhaust passageincludes a sump region communicating in substantially uniformlydistributed relation with the rear region of the turbine means, and asubstantially straight bore communicating with the sump region andextending through the casing means to exhaust through said exit at theextreme rear region of said casing means.

8. In a drill as defined in claim 5 and wherein said valve sectionincludes an air supply passage portion having an eccentric valve chamberregion opening through its rear face and a jogged passage region openingthrough its front face, said trigger section includes an eccentric guidebore opening through its rear face and communicating with said valvechamber region to receive a valve actuating rod, an axial guide bore toreceive a slide rod for actuating the releasable tool holding means anda transversely opening socket intersecting said eccentric guide bore andsaid axial guide bore, said trigger means having a stem portionprojecting through said socket to engage the valve actuating rod and theslide rod for controlling fore and aft shifting thereof. 7 I

9. In a drill as defined in claim 1 and wherein said casing meanscomprises a modular casing assembly that includes a turbine housinghaving a rear attachment section and at least one additional section forsupporting said trigger means and for supporting valve means controlledby said trigger means, each of said sections having a separate endwiseopening air supply passage portion and a separate endwise opening airexhaust passage portion, and means securing said sections in end-to-endcontacting relationship wherein the air supply passage portions are insuccessive registry to define said air supply passage and the airexhaust passage portions are in successive registry to define said airexhaust passage.

10. A pneumatic turbine powered surgical motor apparatus for rotating amedical instrument comprising, in combination, an elongated housinghaving a longitudinal axis, an input end and an output end, a shaftrotatably mounted in said housing concentric with said axis andprojecting from said output end adapted to drive a cutting instrument, apressurized gas connection and an exhaust gas connection defined on saidhousing at said input end, an axial flow turbine having a rotorrotatably mounted in said housing concentric thereto and drivinglyconnected to said shaft, said turbine having an inlet disposed towardsaid housing output end and an exit disposed toward said housing inputend, first passage means longitudinally defined in said housingconcentrically extending about the periphery of said turbine andcommunicating with said pressurized gas connection and said turbineinlet, and second passage means defined in said housing communicatingwith said exhaust gas connection and said turbine exit wherebypressurized gas entering said pressurized gas connection and firstpassage flows toward said housing output end to said turbine inlet,enters said turbine inlet and reverses its direction of flow to flowthrough said turbine toward said housing input end and from said turbineexit to said exhaust gas connection.

11. In a pneumatic turbine powered surgical motor apparatus as in claim10 wherein said first passage means comprises an annular chamberconcentrically disposed about said turbine and said second passage meanscomprises a plurality of passages axially defined in said housingextending between said turbine exit and said exhaust gas connection.

1. In a pneumatically driven turbine type surgical drill that includescasing means having turbine means rotatably mounted therein, releasabletool holding means operable by said turbine means, and trigger means forcontrolling supply of compressed air to said turbine means, theimprovement wherein said casing means has an air flow passage networkincluding an air inlet located rearwardly of said turbine means, an airsupply passage leading from said inlet to a front region of said turbinemeans for rearward flow through said turbine means to impart rotationthereto and an air exhaust passage leading from a rear region of theturbine means to an exit located rearwardly of said turbine means.
 2. Ina drill as defined in claim 1 and wherein said casing means includesconcentric telescoping sleeves encircling said turbine means anddefining an elongated annular air supply passage region for directingincoming air to an annular front region of said turbine means fordirecting the air rearwardly in substantially uniformly distributedrelation into the turbine means.
 3. In a drill as defined in claim 1 andwherein said exhaust passage includes a sump region communicating insubstantially uniformly distributed relation with the rear region of theturbine means, and a substantially straight bore communicating with thesump region and extending through the casing means to exhaust throughsaid exit at the extreme rear region of said casing means.
 4. In a drillas defined in claim 3 and wherein said casing means includes concentrictelescoping sleeves encircling said turbine means and defining anelongated annular air supply passage region for directing incoming airto an annular front region of said turbine means for directing the airrearwardly in substantially uniformly distributed relation into theturbine means.
 5. In a pneumatically driven turbine type surgical drillthat includes casing means having turbine means rotatably mountedtherein, releasable tool holding means operable by said turbine means,and trigger means for controlling supply of compressed air to saidturbine means, the improvement wherein said casing means comprises amodular casing assembly that includes a turbine housing having a rearattachment section, a trigger section, a valve section and a valvecylinder section in successive axial alignment, each of said sectionshaving a separate endwise opening air supply passage portion and aseparate endwise opening air exhaust passage portion, and means securingsaid sections in end to end contacting relationship wherein the airsupply passage portions are in successive registry to define an airsupply passage and the air passage portions are in successive registryto define an air exhaust passage.
 6. In a drill as defined in claim 5and wherein said turbine housing includes concentric telescoping sleevesencircling said turbine means and defining an elongated annular airsupply passage region for directing incoming air to an annular frontregiOn of said turbine means for directing the air rearwardly insubstantially uniformly distributed relation into the turbine means. 7.In a drill as defined in claim 6 and wherein said exhaust passageincludes a sump region communicating in substantially uniformlydistributed relation with the rear region of the turbine means, and asubstantially straight bore communicating with the sump region andextending through the casing means to exhaust through said exit at theextreme rear region of said casing means.
 8. In a drill as defined inclaim 5 and wherein said valve section includes an air supply passageportion having an eccentric valve chamber region opening through itsrear face and a jogged passage region opening through its front face,said trigger section includes an eccentric guide bore opening throughits rear face and communicating with said valve chamber region toreceive a valve actuating rod, an axial guide bore to receive a sliderod for actuating the releasable tool holding means and a transverselyopening socket intersecting said eccentric guide bore and said axialguide bore, said trigger means having a stem portion projecting throughsaid socket to engage the valve actuating rod and the slide rod forcontrolling fore and aft shifting thereof.
 9. In a drill as defined inclaim 1 and wherein said casing means comprises a modular casingassembly that includes a turbine housing having a rear attachmentsection and at least one additional section for supporting said triggermeans and for supporting valve means controlled by said trigger means,each of said sections having a separate endwise opening air supplypassage portion and a separate endwise opening air exhaust passageportion, and means securing said sections in end-to-end contactingrelationship wherein the air supply passage portions are in successiveregistry to define said air supply passage and the air exhaust passageportions are in successive registry to define said air exhaust passage.10. A pneumatic turbine powered surgical motor apparatus for rotating amedical instrument comprising, in combination, an elongated housinghaving a longitudinal axis, an input end and an output end, a shaftrotatably mounted in said housing concentric with said axis andprojecting from said output end adapted to drive a cutting instrument, apressurized gas connection and an exhaust gas connection defined on saidhousing at said input end, an axial flow turbine having a rotorrotatably mounted in said housing concentric thereto and drivinglyconnected to said shaft, said turbine having an inlet disposed towardsaid housing output end and an exit disposed toward said housing inputend, first passage means longitudinally defined in said housingconcentrically extending about the periphery of said turbine andcommunicating with said pressurized gas connection and said turbineinlet, and second passage means defined in said housing communicatingwith said exhaust gas connection and said turbine exit wherebypressurized gas entering said pressurized gas connection and firstpassage flows toward said housing output end to said turbine inlet,enters said turbine inlet and reverses its direction of flow to flowthrough said turbine toward said housing input end and from said turbineexit to said exhaust gas connection.
 11. In a pneumatic turbine poweredsurgical motor apparatus as in claim 10 wherein said first passage meanscomprises an annular chamber concentrically disposed about said turbineand said second passage means comprises a plurality of passages axiallydefined in said housing extending between said turbine exit and saidexhaust gas connection.